1. Field of the Invention
The present invention relates generally to an organic light emitting diode (OLED) display. More particularly, the present invention relates to an OLED display to which thin film encapsulation (TFE) technology is applied.
2. Description of the Related Art
An OLED display is a self luminescent display device that has a self luminescent organic light emitting element to display an image. The organic light emitting element may be deteriorated by penetration of external moisture and oxygen, as well as ultraviolet (UV) rays. Deterioration of the organic light emitting element due to such external factors causes a failure of the organic light emitting element and decreases the useful lifespan of the organic light emitting element, and thus packaging technology which seals the organic light emitting element is very important.
Thin film encapsulation technology, which is a packaging technology of the organic light emitting element, is known. Thin film encapsulation technology is technology regarding the covering of a display area of a substrate with a thin film encapsulation layer by alternately stacking at least one layer of an inorganic film and an organic film on the organic light emitting element. The thin film encapsulation layer is essential for embodying a slim OLED display to which a super-thin substrate is applied, and a flexible OLED display to which a flexible film substrate is applied.
However, the thin film encapsulation layer is effective in suppressing penetration of moisture and oxygen according to a stacked direction, i.e., a thickness direction of an inorganic film and an organic film, but it is weak in suppressing penetration of moisture and oxygen in a surface direction of the thin film encapsulation layer and penetration at the edge thereof. Therefore, as organic light emitting elements which are positioned at the edge of a display area deteriorate, a display failure may occur, and the useful lifespan of the OLED display is shortened.
The above information disclosed in this Background section is only for the enhancement of an understanding of the background of the described technology, and therefore it may contain information which does not form the prior art which is already known in this country to a person of ordinary skill in the art.